Producing method for casting large power diesel engine cylinder jacket
Technical field
The present invention relates to a kind of castmethod of cylinder jacket of diesel engine, the excellent Casting Technology of particularly a kind of two-stroke low speed large power diesel engine cylinder jacket.
Background technology
High strength, high-elongation, the requirement of high-wearing feature characteristic of low speed large power diesel engine cylinder jacket its castings material of residing core position and high temperature, the decision of high pressure a particular job environment in the diesel engine operational process.In the Foundry Production of traditional cylinder sleeve, the melting material is: the pig iron, steel scrap and foundry return.Composition is C:3.0-3.5%, Si:1.8-2.5%, Mn:0.6-1.2%, P:1.2-1.5%, S:<0.1%, the alloy that adds has Cr, Mo, Cu, B, V etc., though the cylinder sleeve of this explained hereafter can obtain metallographic structure preferably and graphite form, mechanical property is difficult to satisfy the requirement of ship rule.
Summary of the invention
The purpose of this invention is to provide a kind of mechanical property and meet ship rule standard-required, improve the cylinder sleeve quality, reduce scrap rate, make the cylinder sleeve of production obtain the producing method for casting large power diesel engine cylinder jacket of good operating performance.
The object of the present invention is achieved like this: a kind of producing method for casting large power diesel engine cylinder jacket, it is characterized in that: in weight part, with pig iron 10-20 part, steel scrap 40-50 part, after foundry returns 40-50 part is mixed, adding carburelant in cold stock melts, each constituent content of adjustment reached after the spectrum chemical examination was carried out in sampling behind the molten iron is melting: C:3.05-3.15%, Si:1.2-1.35%, Mn:0.5-0.6%, P:0.23-0.27%, S:0.05-0.06%, Cu:1.25-1.35%, V:0.14-0.16%, B:0.026-0.032%, the molten iron for preparing is warming up to 1500 ℃, casts after calm 10 minutes.Foundry returns is the rising head clout that cuts down in cylinder sleeve waste material and the diesel cylinder sleeve castingprocesses of scrapping after the fragmentation.The raw material that adds is counted 10 parts of the pig iron, 40 parts of steel scraps, 50 parts of foundry returns with weight part.
Producing method for casting large power diesel engine cylinder jacket provided by the present invention, by adjusting the pig iron, steel scrap, the ratio of foundry returns, reach proper mechanical capacity and metallographic structure, because of the heredity of the pig iron comparatively outstanding, adding too much to cause the crystal grain of foundry goods thick, foundry returns is because of through repeatedly remelting, be the less high-quality batching of detrimental impurity, the adding of steel scrap can improve the foundry goods mechanical property by a relatively large margin, and novel process adopts the steel scrap of a spot of pig iron and big proportioning, the proportioning process of foundry returns, adopt the method for carburetting to adjust the foundry goods carbon content, improved the quality of the cylinder sleeve of casting to obtain the high-quality molten iron that conformance with standard requires.
Embodiment
Embodiment one:
In the casting smelting process of cylinder sleeve, adopt the pig iron of 100Kg, the steel scrap of 400Kg, Mn content is less than 0.5% in the steel scrap, and the foundry returns of 500Kg, foundry returns are scrapping the cylinder sleeve waste material and cutting the rising head clout that cuts off in the diesel cylinder sleeve castingprocesses after the fragmentation.Add above-mentioned material in the cold stock and add carburelant, carburelant adopts graphite granule, heat and melt, wait to melt and adjust again after the chemical examination of molten iron sampling carrying out spectrum in the span of control that each element reaches C:3.05-3.15%, Si:1.2-1.35%, Mn:0.5-0.6%, P:0.23-0.27%, S:0.05-0.06%, Cu:1.25-1.35%, V:0.14-0.16%, B:0.026-0.032%.The molten iron for preparing is warming up to 1500 ℃, casts after calm 10 minutes.
Embodiment two:
In the casting smelting process of cylinder sleeve, adopt the pig iron of 150Kg, the steel scrap of 450Kg, Mn content is less than 0.5% in the steel scrap, and the foundry returns of 450Kg, foundry returns are scrapping the cylinder sleeve waste material and cutting the rising head clout that cuts off in the diesel cylinder sleeve castingprocesses after the fragmentation.Add above-mentioned material in the cold stock and add carburelant, carburelant adopts graphite granule, heat and melt, wait to melt and adjust again after the chemical examination of molten iron sampling carrying out spectrum in the span of control that each element reaches C:3.05-3.15%, Si:1.2-1.35%, Mn:0.5-0.6%, P:0.23-0.27%, S:0.05-0.06%, Cu:1.25-1.35%, V:0.14-0.16%, B:0.026-0.032%.The molten iron for preparing is warming up to 1500 ℃, casts after calm 10 minutes.
In castingprocesses, adjust each component content, add graphite granule when adjusting the content of C; Add 75 ferrosilicon when adjusting Si content; Add ferromanganese when adjusting Mn content; Add ferrophosphorus when adjusting P content; Add copper coin alloy or brass when adjusting the content of Cu; Add alum iron when adjusting the content of V; Add ferro-boron when adjusting the content of B.The content of S is generally higher, because the affiliation that adds of manganese generates manganese sulfide, makes that the content of sulphur reaches prescribed value in the molten iron.Pour into a mould after the molten iron calmness through preparing.The tensile strength 265Mpa of net result, unit elongation 0.45%, graphite form A
4Level.The tensile strength of S46 machine 3# is 285Mpa, unit elongation 0.42%, graphite form A
3-4Level.